Neuro-oncology Flashcards
What is the most common type of tumour in the brain?
Secondary to metastasis
What are the most common metastases to the brain? Describe the prognosis and location of these.
- Lung
- Breast
- Melanoma
These usually have a poor prognosis and are difficult to manage. They are usually found the gray-white junction as this is where emboli from the primary tumour can get lodged.
How can CNS tumours be classified?
By locations:
- Intra-axial (parenchyma)
- Extra-axial: bone, meninges
By histology:
- Astrocytes
- Oligodendrogliomas
- Meningiomas
- Embryonal cells
What are the signs and symptoms of a brain tumour?
General:
- Headache
- Signs of raised ICP
- Specific to location
Supra-tentorial:
- Cognitive deficit
- Personality changes
- Seizures
Sub-tentorial:
- Ataxia
- Cerebral nerve palsy
What is the aetiology of brain tumours?
Largely unknown but some are associated with genetic mutations and associated disease
Neurofibromatosis 1: neurofibroma, pilocytic astrocytoma
Neurofibromatosis 2: schwannoma, meningioma
Tuberous sclerosis: hamartoma
Von Hippel Lindau: hemangioblastoma
How are brain tumours investigated?
Imagine:
- MRI
- CT
Histology:
- Biopsy
How are brain tumours classified?
WHO system:
- Type
- Grade
- Genetic profile
How are brain tumours managed?
- Maximal safe resection
- Radiotherapy
- Chemotherapy
What is the most common primary tumour of the CNS?
Glial tumours, these can be:
- Diffuse infiltration type
- Well circumscribed type
Describe the well circumscribed types of glial tumours
These are usually grades 1 to 2, and are more common in children. They are associated with mutations in the MAPK pathway. They rarely become malignant and the most common kind is a pilocytic astrocytoma.
Pilocytic astrocytoma:
- Present in the 1st or 2nd decade
- Common in neurofibromatosis 1
- MRI: well circumscribed, cystic, enhancing
- Usually in the cerebellum
- Histology: piloid hairy cell
Describe the diffuse infiltration type of glial cells
These are at least a grade 2 and are more common in adults. They are associated with the IDH1/2 mutation. They commonly are malignant. The most important to consider are glioblastomas, glioblastoma multiforme and oligodendrogliomas.
Glioblastoma:
- In the cerebral hemispheres
- Presents at 20-40 years
- Over 80 percent have the IDH1/2 mutation
Glioblastoma multiforme
- Present in older age
- Fast growing, grade 4 tumour
- 90 percent are de novo GBM, the rest are progression from a glioblastoma
- MRI: heterogenous appearance
- Histology: large mitotic activity
- Neoangiogenesis and necrosis
Oligodendrogliomas
- Present at 20-40 years
- Slow growing tumours
- A long history of seizures
- All have the IDH1/2 mutation and a codeletion of 1p/19q
- Histology: fried egg appearance
Describe meningiomas
These are most common in those above the age of 40, and are associated with neurofibromatosis 2. They present with focal symptoms and over 80 percent are grade one, with the vast majority of the remaining being grade 2. They are slow growing tumours.
MRI:
- Attached to dura
- Push brain away
- Encapsulated
Classification:
- 15 histological types
- 3 grades
- Based on growth speed and brain invasion
Describe medulloblastoma
This is the second most common primary brain tumour in children, and is a fast growing, grade 4 embryonal tumour. It is found in the cerebellum (centrally in children, peripherally in adults) and has four types.
Histology: small blue cell tumours
